Hyperthyroidism may cause abnormalities in glucose tolerance, and in severe cases, may meet the criteria for a diagnosis of diabetes mellitus, so prompt medical attention is recommended. Hyperthyroidism, known as hyperthyroidism, is caused by an increase in the synthesis and secretion of thyroid hormones by the thyroid gland, which can lead to a series of hypermetabolic symptoms such as fear of heat, palpitations, excessive sweating, and an increase in food intake and weight loss. The thyroid hormone in hyperthyroidism accelerates the absorption of glucose and galactose in the small intestine, which makes glucose available to adipose and muscle tissues faster, and to some extent inhibits the secretion of insulin, resulting in the release of hyperglycemia, and so patients with hyperthyroidism may have abnormal glucose tolerance. Patients with hyperthyroidism also suffer from sympathetic excitation, especially increased secretion and activity of catecholamines, which are insulin antagonist hormones, so they have an effect on the hypoglycemic effect of insulin. The high metabolic state of hyperthyroidism also accelerates the breakdown of insulin, which increases the body’s demand for insulin and contributes to the condition of diabetes. Therefore, hyperthyroidism patients should be under the guidance of the doctor to treat hyperthyroidism at the same time, but also need to monitor blood glucose, to understand whether there is an abnormality of glucose metabolism, hyperthyroidism treatment at the same time but also control blood glucose.